6 Early Warning Signs of a Termite Infestation

Termites cause over $5 billion in property damage annually in the United States. The earliest warning signs include mud tubes along foundation walls, hollow-sounding wood, discarded wings near windowsills, frass deposits, tight-fitting doors, and bubbling paint. Spotting even one of these clues warrants a professional inspection.

You might never see a termite. That’s what makes them so destructive.

Unlike most household pests, termites operate silently—inside walls, beneath floors, and behind baseboards—consuming wood from the inside out. By the time visible damage appears, a colony may have been active for years. According to the National Pest Management Association (NPMA), termites collectively cause more than $5 billion in property damage every year in the U.S., and most homeowner insurance policies don’t cover a cent of it.

The good news? Termites do leave clues. They’re subtle, easy to dismiss, and often mistaken for ordinary wear and tear—but they’re there. Knowing what to look for can mean the difference between a $300 treatment and a $30,000 structural repair.

This guide walks you through six early warning signs of a termite infestation that every homeowner should know, where to find them, and what to do if you spot them.

What Are the First Signs of Termites in a Home?

Before diving into each warning sign, it helps to understand the two most common termite species in the U.S.: subterranean termites and drywood termites. Each leaves slightly different evidence, but both cause serious structural damage if left unchecked.

Keeping this distinction in mind will help you narrow down what you’re dealing with—and where to look.

Sign #1: Mud Tubes Along Walls or the Foundation

Mud tubes are one of the clearest indicators of subterranean termite activity. These pencil-width tunnels—built from soil, wood particles, and termite saliva—serve as protected highways between the colony underground and the wood above.

You’ll typically find them:

• Along the base of exterior walls
• Across concrete foundations and crawl space walls
• Running up the sides of support beams or piers

What to do: Break open a section of the tube. If it’s active, you’ll spot live termites inside. Even an empty tube doesn’t mean the threat has passed—colonies often abandon and rebuild tunnels in adjacent areas.

Sign #2: Hollow or Papery-Sounding Wood

Healthy structural wood sounds solid when you knock on it. Wood that termites have hollowed out produces a distinctive dull thud or papery crinkle—because the interior has been consumed, leaving only a thin shell.

Run your knuckle along baseboards, door frames, window sills, and wooden support beams. Pay close attention to areas close to moisture sources, such as bathrooms and kitchens, since termites seek out soft, damp wood first.

A flathead screwdriver is a useful diagnostic tool here. Press the tip gently into a suspicious area. If it punctures with very little resistance, that wood has likely been compromised.

Sign #3: Discarded Wings Near Windows and Doors

Every spring (and sometimes fall), termite colonies release reproductive swarmers—winged adults that fly out to establish new colonies. After landing, they shed their wings almost immediately, leaving behind small, uniform piles near light sources, windowsills, and door frames.

Termite wings are:

• Equal in length (both pairs match)
• Translucent or slightly milky in color
• Roughly ¼ to ½ inch long

If you spot piles of wings—even just a few—treat it as a serious red flag. Swarming indicates an established, mature colony nearby.

Sign #4: Frass (Termite Droppings)

Drywood termites push their excrement out of tiny holes in the wood as they tunnel through it. The result is a small, mound-like pile of what looks like sawdust or fine coffee grounds below an entry hole.

Frass pellets are:

• Six-sided and ridged (visible under magnification)
• Typically tan, brown, or black
• Found in small piles on windowsills, floors, or furniture

One key distinction: subterranean termites use their frass as building material and rarely deposit it externally. So frass on the surface almost always points to a drywood infestation.

Sign #5: Doors and Windows That Suddenly Stick

If a door or window that once opened smoothly starts sticking without any obvious reason—no recent rain, no humidity spike—termite damage may be the cause. As termites consume wood framing, the structural integrity shifts. Wood warps. Frames fall slightly out of alignment.

This sign is easy to miss because homeowners often blame it on seasonal changes. The key differentiator is location: termite-related sticking typically occurs in interior frames, not just exterior-facing ones, and progresses gradually without a clear seasonal pattern.

Check the frame edges for the papery texture or darkened wood mentioned in Sign #2. The combination of both is a strong indicator.

Sign #6: Bubbling or Uneven Paint on Walls

Bubbling, peeling, or uneven paint that doesn’t trace back to a water leak can indicate termite activity behind the wall. As termites eat through wood and introduce moisture into the wall cavity, the surface material—paint or drywall—begins to warp and separate.

This warning sign is especially easy to confuse with ordinary water damage. A few ways to tell the difference:

• Water damage usually has a visible source nearby (leaky pipe, roof damage)
• Termite damage may appear without any obvious moisture source
• Pressing lightly on bubbled areas over termite-damaged drywall often produces a hollow or crunchy feel

If you notice this alongside any other signs on this list, the probability of an active infestation rises considerably.

How Quickly Can Termites Cause Serious Damage?

A single subterranean termite colony can contain anywhere from 60,000 to one million workers, according to the University of Kentucky College of Agriculture. A colony of that size can eat through a one-foot length of 2×4 lumber in roughly five months under the right conditions.

That pace accelerates when multiple colonies are active on the same property—which is not uncommon in warmer, humid climates like those found throughout the South and Southeast United States.

What to Do If You Spot These Warning Signs

Finding one of these signs warrants attention. Finding two or more calls for immediate action.

Start by documenting what you observe—take photos, note the locations, and track whether the signs worsen over days or weeks. Then contact a licensed pest control professional for a full inspection. Most reputable companies offer free or low-cost inspections, and a certified inspector can confirm whether damage is active or historical.

Avoid disturbing suspected activity zones before the inspection. Spraying over-the-counter pesticides into mud tubes or frass holes can scatter the colony, making it harder to locate and eliminate.

Protect Your Home Before the Problem Starts

For homeowners in moderate-to-high-risk zones, annual termite inspections are a sound investment—often less than $100 per year, compared to thousands in potential repairs. Preventive measures like keeping mulch away from the foundation, fixing moisture issues promptly, and storing firewood off the ground significantly reduce the conditions termites favor.

Catching a termite infestation early isn’t luck. It’s the result of knowing what to look for and acting on what you find.

Frequently Asked Questions

What is the most common first sign of termites?
Mud tubes along the foundation or base of exterior walls are among the most reliable early indicators of subterranean termites—the most common termite species in the U.S. Discarded wings near windows are also frequently the first visible sign homeowners notice.

Can termites cause damage without any visible signs?
Yes. Termites work inside wood structures, so significant damage can accumulate before any external signs appear. This is why annual professional inspections are recommended, particularly in high-risk regions.

How do I tell the difference between termite damage and water damage?
Termite damage typically produces hollow-sounding wood, frass deposits, or mud tubes. Water damage is usually traced to a visible source (leaking pipe, roof issue) and may show water staining. When neither cause is obvious, a professional inspection is the safest next step.

Are termites active year-round?
Termite colonies are active year-round in warm climates. In cooler regions, activity slows in winter but rarely stops entirely, especially for colonies established deep in structural wood or close to heat sources inside the home.

How much does termite treatment cost?
According to HomeAdvisor, termite treatment costs in the U.S. range from $230 to $930 on average, depending on the infestation size, treatment method, and geographic location. Whole-structure fumigation for severe drywood infestations can exceed $2,500.

Do termites only attack old homes?
No. Termites target wood regardless of a home’s age. Newly constructed homes with improper soil treatment or wood-to-soil contact can be infested within months of completion.